Buggy code:
public class CollectionPlugin extends XWikiDefaultPlugin implements XWikiPluginInterface { protected CollectionActivityStream collectionActivityStream ; private EntityReferenceSerializer < String > defaultEntityReferenceSerializer ; private DocumentReferenceResolver < String > currentDocumentReferenceResolver ; private AttachmentReferenceResolver < String > currentAttachmentReferenceResolver ; public CollectionPlugin ( String name , String className , XWikiContext context ) { } public String getName ( ) { } public void init ( XWikiContext context ) { } public void virtualInit ( XWikiContext context ) { } private void addDebug ( String string ) { } public Api getPluginApi ( XWikiPluginInterface plugin , XWikiContext context ) { } public boolean exportToXAR ( String packageName , List selectList , boolean withVersions , XWikiContext context ) throws XWikiException , IOException { } public void exportWithLinks ( String documentName , String type , XWikiContext context ) throws Exception { } public void exportWithLinks ( String documentName , List < String > selectlist , String type , XWikiContext context ) throws Exception { } public void exportWithLinks ( String packageName , String documentName , List < String > selectlist , String type , XWikiContext context ) throws Exception { } public void exportWithLinks ( String packageName , String documentName , List < String > selectlist , boolean ignoreInitialPage , String type , XWikiContext context ) throws Exception { } public void exportWithLinks ( String packageName , XWikiDocument doc , List < String > selectlist , boolean ignoreInitialPage , String type , XWikiContext context ) throws Exception { } public void exportWithLinks ( String packageName , XWikiDocument doc , List < String > selectlist , boolean ignoreInitialPage , String type , String pdftemplatepage , XWikiContext context ) throws Exception { } public String getRenderedContentWithLinks ( String documentName , XWikiContext context ) throws Exception { } public String getRenderedContentWithLinks ( String documentName , List < String > selectlist , boolean ignoreInitialPage , XWikiContext context ) throws Exception { } public String getRenderedContentWithLinks ( XWikiDocument doc , List < String > selectlist , boolean ignoreInitialPage , XWikiContext context ) throws Exception { } public void getRenderedContentWithLinks ( XWikiDocument doc , XDOM xdom , List < String > selectlist , List < String > includedList , List < String > headerIds , XWikiContext context ) throws Exception { } protected void appendChild ( String mainDocName , String childDocumentName , XDOM xdom , List < String > selectlist , List < String > includedList , List < String > headerIds , XWikiContext context ) throws Exception { } protected List < String > updateXDOM ( XWikiDocument doc , XDOM xdom , List < String > selectlist , List < String > headerIds ) throws Exception { } public List < String > getLinks ( String documentName , String space , XWikiContext context ) throws Exception { } public List < String > getLinks ( XWikiDocument doc , XDOM xdom , String space ) throws Exception { } public List < ListItem > getLinksTreeList ( String documentName , XWikiContext context ) throws Exception { } public List < ListItem > getLinksTreeList ( String documentName , String space , XWikiContext context ) throws Exception { } public void getLinksTreeList ( String documentName , String space , List < ListItem > treeList , List < String > safeList , XWikiContext context ) throws Exception { } public List < String > getLinkedPages ( XWikiDocument document , XWikiContext context ) { } public String getCollectionsClassName ( XWikiContext context ) { } public boolean isCollection ( String docName , XWikiContext context ) { } public boolean isCollection ( XWikiDocument doc , XWikiContext context ) { } public boolean isCollection ( String docName , String className , XWikiContext context ) { } public boolean isCollection ( XWikiDocument doc , String className , XWikiContext context ) { } public List < String > getCollections ( String docName , XWikiContext context ) { } public List < String > getCollections ( String docName , ArrayList < String > pageList , XWikiContext context ) { } public Map < String , String > getCollectionsWithPath ( String docName , XWikiContext context ) { } public Map < String , String > getCollectionsWithPath ( String docName , String path , ArrayList < String > pageList , XWikiContext context ) { } public List < String > getCollections ( String docName , String className , XWikiContext context ) { } public List < String > getCollections ( String docName , String className , ArrayList < String > pageList , XWikiContext context ) { } public Map < String , String > getCollectionsWithPath ( String docName , String className , XWikiContext context ) { } public Map < String , String > getCollectionsWithPath ( String docName , String className , String path , ArrayList < String > pageList , XWikiContext context ) { } public List < String > getBreadcrumbFromParents ( String docName , ArrayList < String > pageList , XWikiContext context ) { try { XWikiDocument doc = context . getWiki ( ) . getDocument ( docName , context ) ; String page = doc . getParent ( ) ; <START_BUG> if ( ( ( ( ( page != null ) & ( ! ( page . equals ( "" ) ) ) ) && ( ! ( pageList . contains ( page ) ) ) ) && ( ! ( page . equals ( "XWiki.XWikiGuest" ) ) ) ) && ( ! ( page . equals ( "XWiki.XWikiUsers" ) ) ) ) { <END_BUG> pageList . add ( page ) ; return getBreadcrumbFromParents ( page , pageList , context ) ; } else { return pageList ; } } catch ( XWikiException e1 ) { return pageList ; } } public List < String > getBreadcrumb ( String docName , XWikiContext context ) { } }

Fix:
if ( ( ( ( ( page != null ) && ( ! ( page . equals ( "" ) ) ) ) && ( ! ( pageList . contains ( page ) ) ) ) && ( ! ( page . equals ( "XWiki.XWikiGuest" ) ) ) ) && ( ! ( page . equals ( "XWiki.XWikiUsers" ) ) ) ) {